The instant invention relates to a method of eliminating canine cauda equina syndrome. Specifically, the method disclosed substantially reduces or eliminates pinching of nerves between the last (seventh) lumbar vertebrae (L.sub.7) and the first sacral vertebrae (S.sub.1).
Cauda equina syndrome occurs when the sacral and caudal nerves, the cauda equina, passing through the juncture of the seventh lumbar vertebrae (L.sub.7) and the first sacral vertebrae (S.sub.1) are compressed as a result of a degenerative disc between L.sub.7 and S.sub.1. Additionally, the peripheral nerves exiting the spine between L.sub.7 and S.sub.1 may be compressed. The fibrous components of the L.sub.7 S.sub.1 disc and the ligamentum flavum, which covers the dorsal juncture between the vertebrae, protrude into the cavity through which the nerves pass. In minor cases, the animal will exhibit discomfort when it tenses or when it attempts to move its hind body portion. In more severe cases, the animal will suffer extreme discomfort and will probably elect to remain immobile as much as possible. Because the nerves affected control voluntary and involuntary body functions, the animal may eventually lose control of urinary and rectal functions as well as reproductive ability.
Known procedures for minimizing or eliminating cauda equina syndrome include a laminectomy for removing a portion of either or both L.sub.7 and S.sub.1 vertebrae. This accomplishes the desired decompression of the nerves passing therethrough, but results in an unstable spinal column and ultimately in a useless animal.
Another known method involves fusing the vertebrae about the L.sub.7 S.sub.1 juncture from the ventral side of the spinal column. Bone spurs will generally be present, thereby increasing the difficulty of the operation. Yet another known method of reducing cauda equina syndrome is to remove the ligamentum flavum from the dorsal portion of the L.sub.7 S.sub.1 juncture. Finally, a discectomy of the dorsal annulus fibrosis may reduce the animal's pain.
All of the known methods will provide some degree of relief for the animal, but are not successful in the long run. These known procedures leave portions of the intervertebral disc or ligamentum flavum which may ultimately compress the nerves passing through the L.sub.7 S.sub.1 juncture or leave the spine unstable.
It is therefore an object of the instant invention to provide a method of eliminating canine cauda equina syndrome, which is a one-time procedure and provides continuous relief from nerve compression produced by the breakdown of the intervertebral disc and collapse of the L.sub.7 S.sub.1 intervertebral disc space.
Another object of the instant invention is to provide a method of eliminating canine cauda equina syndrome by fixing L.sub.7 relative S.sub.1 in a position whereby compression is not applied on the nerves passing through the L.sub.7 S.sub.1 juncture.
The instant invention teaches a method of eliminating canine cauda equina syndrome by dorsally separating S.sub.1 and its associated sacral vertebrae from L.sub.7, thereby relieving pressure on the nerves passing through the L.sub.7 S.sub.1 juncture. L.sub.7 is fixed relative S.sub.1 with the caudal articular processes on L.sub.7 substantially aligning with their respective articular facets on S.sub.1. L.sub.7 may be fixed relative S.sub.1 by fusing L.sub.7 to S.sub.1, by anchoring L.sub.7 relative S.sub.1 by inserting a pin through the articular facet on each caudal articular process on L.sub.7 and through the respective articular facet on S.sub.1, or by a combination of fusing and inserting a pin in both vertebrae.
Other objects and advantages of the instant invention will become more fully apparent as the description which follows is read in conjunction with the drawings.